Nicotine is a well known, highly characterized alkaloid that can be isolated from the dried leaves of Nicotiana tabacum. Its numerous commercial uses include utilities such as a fumigant, an insecticide and the like. It is therapeutically valuable in the treatment of the smoking withdrawal syndrome.
Smoking, e.g., cigarettes, pipes or cigars, results in the uptake of nicotine by the body. As nicotine is a stimulant, the smoker experiences a pleasant sensation arising from the uptake of nicotine in the body—this pleasant sensation is addictive. Whilst nicotine itself may not be particularly harmful to the human body, smoking may be associated with health hazards not necessarily associated with administration of nicotine itself, but e.g. associated with inhalation of tar.
As a result, non-smoking methods have been devised to administer nicotine to the body. These include nicotine-containing chewing gums, nicotine-impregnated dermal patches, nicotine inhalers and the like. A variety of patents have disclosed such products.
Incorporation of nicotine in its pure form into a nicotine delivery product has turned out not to be advantageous, because nicotine is relatively volatile so that the resulting nicotine delivery products are not always adequately stable, losing nicotine relatively rapidly over time.
One advance has been the development of nicotine polacrilex resins (NPR), where nicotine molecules are bound to a cationic exchange resin. Using an NPR instead of nicotine base in a nicotine delivery product significantly improves the product's stability. Adequate release is also possible. NPR is used e.g. in various nicotine-containing chewing gum compositions.
U.S. Pat. No. 6,586,449 claims a method for preparing a nicotine-containing composition having a nicotine release rate of not less than 70% over a 10 minute period said method comprising (a) mixing an aqueous solution of an organic polyol with a cation exchange resin selected from the group consisting of (i)—a methacrylic, weakly acidic type of resin containing carboxylic functional groups, (ii)—a polystyrene, strongly acidic type of resin containing sulphonic functional groups, and (iii)—a polystyrene, intermediate acidic type of resin containing phosphonic functional groups, thereby forming a cation exchange resin mixture having some of its ion exchange sites partially blocked with said polyol; (b) admixing with said mixture of step (a) an aqueous solution of nicotine to form a nicotine-coated cation exchange resin admixture; and (c) removing water from said admixture to produce said nicotine composition having a nicotine release rate of not less than 70% over a 10 minute period. The resulting dry nicotine composition can presumably be used to manufacture a nicotine delivery product such as a nicotine-containing chewing gum, by mixing the dry nicotine composition with further ingredients such as gum base and a sweetener.
When mixing a cation exchange resin, a polyol, and nicotine, U.S. Pat. No. 6,586,449 teaches preparation of an aqueous slurry as an intermediate and the removal of water for isolating the nicotine composition. The step of removing water is considered by U.S. Pat. No. 6,586,449 to be essential, and its prior art discussion makes it clear that its author considered that any nicotine-containing system which comprises water must be unstable.
A disadvantage of the prior art method for producing a nicotine-containing composition is that it is time consuming as a consequence of the water-removal step, which also requires a considerable amount of energy to be expended. Furthermore, the amounts of water needed reduces the capacity of a given production plant. The amount of water removed to produce the nicotine delivery product is above 90% by weight of added water and the water content of the nicotine delivery product after removal of water is typically only a few percent by weight of the nicotine delivery. Finally, the dry NPR has a tendency to dust when no polyol is used.
The present invention aims to solve the aforementioned deficiencies of the prior art, by providing a method of manufacturing a nicotine delivery product (such as nicotine-containing chewing gums, nicotine-containing lozenges, nicotine-containing pastilles, nicotine-containing tablets, nicotine-containing patches, nicotine-containing inhalers and nicotine-containing nasal sprays) which method is simpler, faster and/or more energy-efficient than the methods known from the prior art.